deployment requires restart due to cloudstats daemon TypeError

After deploying cloudstats charm, attaching snap resource, and adding keystone relation, the cloudstats snap remains in an error state.

Traceback:

Jul 10 16:27:40 juju-d7d014-1-lxd-9 systemd[1]: Started Service for snap application cloudstats.cloudstats.
Jul 10 16:27:41 juju-d7d014-1-lxd-9 cloudstats.cloudstats[24509]: Traceback (most recent call last):
Jul 10 16:27:41 juju-d7d014-1-lxd-9 cloudstats.cloudstats[24509]: File "/snap/cloudstats/x1/bin/cloudstats", line 11, in <module>
Jul 10 16:27:41 juju-d7d014-1-lxd-9 cloudstats.cloudstats[24509]: load_entry_point('cloudstats==0.1', 'console_scripts', 'cloudstats')()
Jul 10 16:27:41 juju-d7d014-1-lxd-9 cloudstats.cloudstats[24509]: File "/snap/cloudstats/x1/lib/python3.6/site-packages/cloudstats/daemon.py", line 89, in main
Jul 10 16:27:41 juju-d7d014-1-lxd-9 cloudstats.cloudstats[24509]: daemon = StatsDaemon(sys.argv[1:])
Jul 10 16:27:41 juju-d7d014-1-lxd-9 cloudstats.cloudstats[24509]: File "/snap/cloudstats/x1/lib/python3.6/site-packages/cloudstats/daemon.py", line 21, in __init__
Jul 10 16:27:41 juju-d7d014-1-lxd-9 cloudstats.cloudstats[24509]: self.openstack = self.setup_openstack()
Jul 10 16:27:41 juju-d7d014-1-lxd-9 cloudstats.cloudstats[24509]: File "/snap/cloudstats/x1/lib/python3.6/site-packages/cloudstats/daemon.py", line 35, in setup_openstack
Jul 10 16:27:41 juju-d7d014-1-lxd-9 cloudstats.cloudstats[24509]: return OpenstackStats()
Jul 10 16:27:41 juju-d7d014-1-lxd-9 cloudstats.cloudstats[24509]: File "/snap/cloudstats/x1/lib/python3.6/site-packages/cloudstats/opensdk.py", line 21, in __init__
Jul 10 16:27:41 juju-d7d014-1-lxd-9 cloudstats.cloudstats[24509]: self.connection = self.get_connection()
Jul 10 16:27:41 juju-d7d014-1-lxd-9 cloudstats.cloudstats[24509]: File "/snap/cloudstats/x1/lib/python3.6/site-packages/cloudstats/opensdk.py", line 40, in get_connection
Jul 10 16:27:41 juju-d7d014-1-lxd-9 cloudstats.cloudstats[24509]: cacert=self.config["cacert"].get(str),
Jul 10 16:27:41 juju-d7d014-1-lxd-9 cloudstats.cloudstats[24509]: File "/snap/cloudstats/x1/lib/python3.6/site-packages/openstack/connection.py", line 386, in __init__
Jul 10 16:27:41 juju-d7d014-1-lxd-9 cloudstats.cloudstats[24509]: **kwargs)
Jul 10 16:27:41 juju-d7d014-1-lxd-9 cloudstats.cloudstats[24509]: File "/snap/cloudstats/x1/lib/python3.6/site-packages/openstack/config/__init__.py", line 36, in get_cloud_region
Jul 10 16:27:41 juju-d7d014-1-lxd-9 cloudstats.cloudstats[24509]: return config.get_one(options=parsed_options, **kwargs)
Jul 10 16:27:41 juju-d7d014-1-lxd-9 cloudstats.cloudstats[24509]: File "/snap/cloudstats/x1/lib/python3.6/site-packages/openstack/config/loader.py", line 1101, in get_one
Jul 10 16:27:41 juju-d7d014-1-lxd-9 cloudstats.cloudstats[24509]: auth_plugin = loader.load_from_options(**config['auth'])
Jul 10 16:27:41 juju-d7d014-1-lxd-9 cloudstats.cloudstats[24509]: File "/snap/cloudstats/x1/lib/python3.6/site-packages/keystoneauth1/loading/base.py", line 164, in load_from_options
Jul 10 16:27:41 juju-d7d014-1-lxd-9 cloudstats.cloudstats[24509]: return self.create_plugin(**kwargs)
Jul 10 16:27:41 juju-d7d014-1-lxd-9 cloudstats.cloudstats[24509]: File "/snap/cloudstats/x1/lib/python3.6/site-packages/keystoneauth1/loading/base.py", line 125, in create_plugin
Jul 10 16:27:41 juju-d7d014-1-lxd-9 cloudstats.cloudstats[24509]: return self.plugin_class(**kwargs)
Jul 10 16:27:41 juju-d7d014-1-lxd-9 cloudstats.cloudstats[24509]: TypeError: __init__() got an unexpected keyword argument 'auth_url'

Doing a snap restart fixes the issue, and cloudstats begins to work again.

Steps to reproduce:

juju deploy ./charm-cloudstats cloudstats --series xenial --config ./config.yaml --to lxd:1 --constraints "spaces=oam-space,internal-space"
juju attach-resource cloudstats cloudstats=./cloudstats_0.0.6_amd64.snap
juju add-relation keystone:identity-admin cloudstats:openstack-admin

# wait for charm to settle
# check snap status
juju run --unit cloudstats/0 "systemctl status snap.cloudstats.cloudstats.service"

# restart cloudstats snap
snap restart cloudstats